WO2000044986A1

WO2000044986A1 - Method of manufacturing pulp mold formed body

Info

Publication number: WO2000044986A1
Application number: PCT/JP2000/000114
Authority: WO
Inventors: Akira Nonomura
Original assignee: Kao Corporation
Priority date: 1999-01-29
Filing date: 2000-01-12
Publication date: 2000-08-03
Also published as: DE60045819D1; CN1170035C; US6797120B2; EP1195466A4; US20030209337A1; CN1338017A; EP1195466A1; US6592720B1; EP1195466B1

Abstract

A method of manufacturing a pulp mold formed body, comprising; a first heating and drying process wherein a pulp mold intermediate (15) is formed, the pulp mold intermediate (15) is filled into a recessed part of a heated mold having a recessed part formed corresponding to the outside shape of the pulp mold formed body to be formed, and the pulp mold intermediate (15) is hot-pressed and a second heating; and a second heating and drying process wherein the hot-pressed pulp mold intermediate (15) is heated and dried in a drying furnace after the intermediate (15) is taken out from the heated mold.

Description

Description Manufacturing method of pulp molded article Technical field

The present invention relates to a method for producing a pulp molded article. Background art

As a drying method in the drying step of the method for producing a pulp mold and a molded body, there is a method in which a pulp mold intermediate obtained by papermaking is dried by a predetermined means in a drying furnace. However, since the shape cannot be controlled by this drying method, the dimensional accuracy of the obtained molded body is poor, and the heat transfer efficiency during drying is poor, so that the drying furnace becomes large. Furthermore, the surface properties of the molded body are not good, and the strength of the molded body is poor due to the low pulp density. As another method of the drying method, there is a method in which a pulp mold intermediate obtained by papermaking is placed in a heating mold and hot-pressed as described in JP-A-7-420100. According to this drying method, a compact having good dimensional accuracy can be obtained, and the drying time is shortened due to high heat transfer efficiency. However, drying involves the physical phenomena of supplying the energy required for evaporation by heat transfer, so even if the drying time is shortened, it still requires a longer time than the paper making and dewatering processes . Therefore, a large number of heating dies must be prepared for the number of papermaking dies, which increases equipment costs and manufacturing costs. In addition, if the temperature of the heating mold is increased to shorten the drying time, the molded product is liable to be discolored (burned in some cases). By the way, in the conventional container made of pulp mold, a certain surface strength was required to prevent the attached lapel from peeling or the coated surface from peeling. . In addition, containers made of pulp molded articles are required to have the same flexibility as plastic containers. Disclosure of the invention

Accordingly, an object of the present invention is to provide a method for producing a pulp molded article capable of shortening the drying time and reducing the size of the drying equipment, thereby reducing the production cost. Another object of the present invention is to provide a method for producing a pulp molded article capable of imparting necessary rigidity and flexibility according to the use of the molded article by controlling the density and flexibility while keeping the surface strength constant. With the goal. The present invention relates to a method for producing a pulp molded article by forming a pulp mold intermediate from a pulp slurry by a papermaking mold and heating and drying the pulp mold intermediate.

In the heating and drying step, a first step of loading the pulp mold intermediate into the recess of a heating mold having a recess having a shape corresponding to the outer shape of the pulp molded article to be molded, and hot pressing the pulp mold intermediate And a second step of removing the hot-pressed pulp mold intermediate from the heating mold and heating and drying in a drying furnace to provide a pulp mold molded body. O The present invention is preferably used in the method for producing the pulp molded article. Pulp molded article manufacturing apparatus,

The heating die having the concave portion, the core for pressing the pulp mold intermediate housed in the concave portion of the heating die toward the concave portion, and measuring the water content, weight or temperature of the pulp mold intermediate A first heating and drying means having a measuring device to

A second heating and drying unit having the drying furnace for further heating and drying the pulp mold intermediate that has been heated and dried to a predetermined moisture content by the first heating and drying unit,

A transport for transporting the pulp mold intermediate from the first heating and drying unit to the second heating and drying unit based on data on the moisture content, weight, or temperature of the pulp mold intermediate measured by the measurement device. And an apparatus for manufacturing a pulp molded article having means. BRIEF DESCRIPTION OF THE FIGURES

1 (a) to 1 (d) are schematic views showing a paper making and dewatering step in one embodiment of the method for producing a pulp molded article of the present invention. FIG. 1 (a) shows a paper making step and FIG. ) Is the core insertion step, Fig. 1 (c) is the pressurization / dehydration step, and Fig. 1 (d) is the step of opening the papermaking mold and removing the pulp mold intermediate. FIG. 2 is a schematic diagram showing a second heating and drying step in one embodiment of the method for producing a pulp molded article of the present invention.

FIG. 3 is a perspective view showing an example of a pulp molded article manufactured by the method for producing a pulp molded article of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a method for producing a pulp molded article of the present invention will be described based on preferred embodiments with reference to the drawings. The production method of the present invention roughly includes (1) a papermaking / dewatering step, (2) a first heat-drying step, and (3) a second heat-drying step. A heating and drying step. Fig. 1 shows the papermaking and dewatering steps of these steps.Specifically, Fig. 1 (a) shows the papermaking step, Fig. 1 (b) shows the core insertion step, and Fig. 1 (c) shows Pressurization / dehydration process, Fig. 1 (d) is the process of opening the papermaking mold and removing the pulp mold intermediate. First, a paper making process is performed as shown in FIG. That is, two sets of split molds 11 and 12 are abutted against each other to form a cavity 13 composed of a recess having a predetermined shape. Is injected. Each split mold 1 1, 1 2 is provided with a plurality of communication holes 14 communicating with the cavity 13 from the outer surface thereof. <Also, the inner surface of each split mold 1 1, 1 2 Each is covered by a net (not shown) having a mesh size. The shape of the cavity 13 as the concave portion is not particularly limited. In the present embodiment, the shape of the cavity 13 is a shape corresponding to the outer shape of the pulp molded article to be molded. Next, the inside of the cavity 13 is depressurized by sucking from the outside of the split molds 11 and 12, the moisture in the pulp slurry is sucked, and the pulp fibers are deposited on the inner surface of the cavity 13. As a result, a pulp mold intermediate 15 on which pulp fibers are deposited with a predetermined thickness is formed on the inner surface of the cavity 13. The pulp slurry may be composed of pulp fiber and water, or in addition to these, an inorganic substance such as talc or kaolinite, an inorganic fiber such as glass fiber or carbon fiber, a powder or fiber of a synthetic resin such as polyolefin, or a non-woven fabric. It may contain components such as wood or vegetable fiber and polysaccharides. The amount of these components is preferably 1 to 70% by weight, more preferably 5 to 50% by weight, based on the total amount of the pulp fiber and the components. Pulp fiber, needle Wood pulp such as hardwood or hardwood and non-wood pulp such as bamboo or straw are preferred. Further, the length and thickness of the pulp fiber are preferably 0.1 mm or more and 10 mm or less, and 0.11 111 111 or more and 0.05 mm or less.o Pulp mold intermediate with a predetermined thickness When the body 15 is formed, stop injecting the pulp slurry and completely suck and dehydrate the cavity 13. Subsequently, as shown in FIG. 1 (b), the inside of the cavity 13 is sucked and depressurized, and at the same time, the expandable and contractible core 16 is formed. Insert the core 16 as an elastic body into the cavity 13. The core 16 is inflated like a balloon in the cavity 13 to press the pulp mold intermediate 15 against the inner surface of the cavity 13, thereby imparting the inner shape of the cavity 13 and the pulp mold intermediate. Used to advance pressure dehydration of body 15. The core 16 used in the present embodiment is formed of urethane, fluorine-based rubber, silicone-based rubber, elastomer, or the like, which is excellent in tensile strength, rebound resilience, elasticity, and the like. Next, as shown in FIG. 1 (c), a pressurized fluid is supplied into the core 16 to expand the core 16, and the expanded pulp mold intermediate 15 is used to convert the pulp mold intermediate 15 into a cavity 1. Press it toward the inner surface of 3. Then, the pulp mold intermediate 15 is pressed against the inner surface of the cavity 13 by the expanded core 16, the inner surface shape of the cavity 13 is transferred to the pulp mold intermediate 15, and dehydration proceeds further. I do. As described above, in the present manufacturing method, the shape of the inner surface of the cavity 13 is transferred by pressing the pulp mold intermediate 15 from the inside of the cavity 13 onto the inner surface of the cavity 13, and thus the shape of the inner surface of the cavity 13 is formed. Even if the shape is complicated, the shape of the inner surface of the cavity 13 is accurately transferred to the pulp mold intermediate 15. Become. Furthermore, unlike the conventional manufacturing method, there is no need to use a bonding step, and thus the obtained molded article does not have a seam or a thick portion due to bonding. As a result, the strength of the obtained molded body is increased and the appearance impression is improved. As the pressurized fluid used to expand the core 16, for example, compressed air (heated air), oil (heated oil), and other various liquids are used. Further, the pressure for supplying the pressurized fluid is preferably in the range of 0.01 to 5 MPa, particularly preferably in the range of 0.1 to 3 MPa. The pressurized fluid may be heated. When the shape of the inner surface of the cavity 13 is sufficiently transferred to the pulp mold intermediate 15 and the pulp mold intermediate 15 can be dehydrated to a predetermined moisture content, the core 1 shown in FIG. 6. Drain the pressurized fluid in 6. Then, the core 16 automatically shrinks and returns to its original size. Next, the contracted core 16 is taken out of the cavity 13 and the papermaking mold 10 is opened to take out the wet pulp mold intermediate 15 having a predetermined water content. The pulp mold intermediate 15 taken out is then subjected to a first heating and drying step in first heating and drying means. In the first heating and drying step, the same operation as in the paper making step shown in FIG. 1 is performed, except that neither papermaking nor dehydration is performed. The first heating and drying means includes: a heating mold for forming a cavity (recess) having a shape corresponding to the outer shape of the molded body to be molded by abutting a pair of split molds; And a measuring device for measuring the water content, weight or temperature of the pulp mold intermediate 15 which is pressed against the cavity. In the first heating and drying step, first, the heating mold is heated to a predetermined temperature, and the heated pulp mold intermediate in the heating mold is heated. Load your body. Next, a core (scalable core) similar to the core 16 used in the papermaking process is inserted into the pulp mold intermediate, and a pressurized fluid is supplied into the core to expand the core. The expanded core presses the pulp mold intermediate against the inner surface of the cavity. The material of the core and the supply pressure of the pressurized fluid can be the same as in the papermaking process. Under this condition, the pulp mold intermediate is dried by heating. As a result, the pulp mold intermediate is interposed between the heating mold and the core as an elastic body, hot-pressed by the pressing of both, and the first heat-drying step is performed, and the pulp mold intermediate 15 Heat drying proceeds. The progress of the heating and drying of the pulp mold intermediate 15 is monitored by measuring the water content, weight or temperature of the pulp mold intermediate 15 using the above-described measuring device provided in the first heating and drying means. . Based on the measurement data of the water content, weight, or temperature of the pulp mold intermediate 15 using the above measuring device, the first heating and drying step is completed when these data reach a predetermined value. In the present embodiment, the first heating and drying step is completed based on the data on the water content of the pulp mold intermediate 15. When the pulp mold intermediate has dried to a predetermined moisture content, the pressurized fluid in the core is drained, and the core is contracted to its original size. Then, the contracted core is taken out of the cavity. Further, the heating mold is opened, the pulp mold intermediate having a predetermined moisture content is taken out, and the pulp mold intermediate 15 is conveyed to second heating and drying means described later. Take-out and transport of the pulp mold intermediate 15 include the pulp mold intermediate measured by the measuring device. It is carried out by the specified transport means based on the data of water content, weight or temperature. Removal of the pulp mold intermediate from the heating mold is performed when the water content of the pulp mold intermediate reaches 10 to 40% by weight, particularly 20 to 30% by weight by the hot press. It is effective. In detail, it has been found by the present inventors that in the step of drying the pulp mold intermediate, the drying mechanism changes depending on the water content within the above range. That is, up to a water content of about 30% by weight, the moisture retained between the fibers of the pulp is removed by drying, so that the drying speed is high. Is removed, so that the drying speed is reduced. Therefore, it is more efficient to terminate the first drying step and shift to the second drying step when the water content reaches 40% by weight, which is a stage before the drying rate decreases. On the other hand, since the equilibrium moisture content of the pulp molded article is 5 to 10% by weight under a general environment, the intermediate pulp mold at the time of transition from the first drying step to the second drying step is used. The lower limit of the water content of the body is preferably 10% by weight. Further, when the water content is within the above range, deformation, blister, discoloration, and the like are effectively prevented. Here, the blister means that when the pressurization (hot pressing) is stopped during the heating and drying process, the water in the liquid state becomes steam inside the high pressure pulp mold intermediate. This is a phenomenon in which the volume suddenly increases, delamination occurs inside the pulp mold intermediate, and blisters occur. By terminating the first drying step when the amount of water in the pulp mold intermediate falls to a predetermined value, the generation of blisters is suppressed. Also, if the product is taken out in a state where the water content is too high, the strength of the molded product itself is low, and care must be taken in handling. The term “moisture content of the pulp mold intermediate” used herein refers to the average moisture content of the entire pulp mold intermediate. Therefore, when the pulp mold intermediate has a wall thickness distribution or a water content distribution, even if the average water content is within the above range, there are portions where the water content is partially outside the above range. Sometimes. For example, if there is a part where the water content is less than the above range even though the average water content is within the above range, shorten the time required for the first heat drying step by the hot press. Thus, it is desirable to prevent discoloration or the like from occurring in the pulp mold intermediate. After the first heating and drying step, the pulp mold intermediate having a predetermined moisture content removed from the heating mold is subjected to a second heating and drying step by a second heating and drying means. The second heating and drying step is performed in a drying furnace 20 as shown in FIG. A belt conveyor 21 is provided in the drying oven 20. A plurality of pulp mold intermediates 15, 15, 15,... Move on the belt conveyor while the pulp mold intermediate 15 Irradiation of infrared or far-infrared rays 22, 22, ..., and more preferably by blowing hot air from the top of the drying oven 20 (not shown) to complete drying or moisture content Drying is performed to 5 to 10% by weight. In the second heating and drying step, a plurality of pulp mold intermediates 15 taken out of the heating mold can be heated and dried at a time, so the pulp mold intermediate 15 can be formed only in the first heating and drying step. The heating mold can be used for the next drying earlier than in the case of drying, and the manufacturing cycle is faster. In addition, since it is not necessary to increase the number of heating types to be prepared, equipment costs can be reduced. Further, since the pulp mold intermediate 15 has already been dried to a predetermined moisture content, the drying can be performed in a short time without increasing the size of the drying furnace 20. Thus, in the present invention, by balancing the first heating and drying step and the second heating and drying step, the manufacturing cycle as a whole is improved. And the drying equipment can be reduced in size, and the production cost can be reduced. In addition, the first heat-drying step using a hot press and the second heat-drying step using a drying furnace are performed in this order, so that the first heat-drying step is switched to the second heat-drying step. By appropriately adjusting the moisture content of the pulp mold intermediate, (1) the density and flexibility of the obtained pulp mold molded body can be controlled while maintaining the surface smoothness and surface strength. Life can be extended. For example, regarding (1), when obtaining a pulp molded article having low density and excellent flexibility, the removal of the pulp mold intermediate from the first heating and drying step is not deformed. It is performed within the range of the water content. This smoothes the surface of the pulp mold intermediate and increases the surface strength. However, since the drying performed while pressing with the core is completed when the moisture content reaches a predetermined value, the density of the pulp mold intermediate does not increase. Next, the removed pulp mold intermediate is subjected to a second heating and drying step. As a result, a pulp mold molded article having excellent surface smoothness and surface strength and low density, that is, high flexibility can be obtained. Regarding (2), the first heating and drying step using the core is terminated when the moisture content of the pulp mold intermediate reaches a level that does not excessively increase, so that the core is not excessively heated. Thermal damage is prevented and core life is extended. If the density is produced only in the first heat drying process a highly flexible molded body low, must be performed pressing by core in ^{1 X 1 0 5 ~ 2 X} 1 0 5 P a low pressure across As a result, the surface strength of the obtained molded body is reduced. Also, since the pressing force is low, the adhesion between the pulp mold intermediate and the heating mold decreases, and as a result, the thermal conductivity between the pulp mold intermediate and the heating mold decreases. Therefore, the drying time of the pulp mold intermediate is prolonged. On the other hand, when a molded body having low density and high flexibility is produced only by the second heating and drying step, the surface strength of the obtained molded body is further reduced. The pulp molded article 1 thus obtained is a hollow body having an opening 2 at an upper portion thereof and a body portion 3 and a bottom portion 4 as shown in FIG. It is used as a hollow container particularly suitable for accommodating contents such as. In this pulp molded article 1, the angle between the ground surface of the bottom 4 and the outer surface of the side wall of the body 3 is approximately 90 ° on any side wall. The depth is 50 mm or more. In addition, the body 3 of the molded body 1 has the entire circumference! : A continuous concave portion 5 is formed. Furthermore, the molded article 1 has no seams or thick portions due to bonding. According to the conventional manufacturing method, it is practically impossible to manufacture the shaped body 1 having such a shape, and there are various restrictions on the design of the shaped body. However, according to the manufacturing method of the present invention, the pulp mold It is possible to easily obtain molded articles of various shapes including the molded article 1 with a short production cycle and low production cost (the present invention is not limited to the above embodiment, and various modifications are possible. In the embodiment, the papermaking mold and the heating mold are separately prepared, but instead, the papermaking mold 10 may also serve as the heating mold. In the top press, a pair of male and female heating dies may be used depending on the shape of the pulp molded article to be formed, and in the second heating and drying step, instead of irradiation with infrared rays or far infrared rays, or In addition, irradiation or high frequency of a predetermined frequency, preferably before As described above, hot air of a predetermined temperature may be blown. Drying using infrared rays, far-infrared rays, or hot air is preferred because the apparatus is inexpensive and can efficiently remove moisture. Drying by high-frequency irradiation is suitable for drying thick-walled products because it can be heated at high speed and has high thermal efficiency and can also heat the inside of the object, but the equipment is expensive. In the second heating and drying step, any two or more of these three heating means may be used in combination. After the first heating and drying step, a coating agent may be applied to the surface of the pulp mold intermediate for the purpose of, for example, preventing moisture, and then the second heating and drying step may be performed. This allows simultaneous drying of the coating agent and finish drying of the pulp mold intermediate. Further, the production method of the present invention may be applied to the production of a bottle-shaped hollow molded body in which the opening area of the opening is smaller than the cross-sectional area of the body. Further, the production method of the present invention may be applied to the production of objects such as figurines, in addition to the use as hollow containers used for storing contents. (Examples 1 and 2 and Comparative Example 1)

A pulp molded article was manufactured using the method shown in FIGS. The heating and drying step in Example 1 and Example 2 consisted of a first step of hot-pressing the pulp mold intermediate and a second step of heating and drying in a drying furnace. The heating and drying process in Comparative Example 1 consisted only of a process of heating and drying the pulp mold intermediate in a drying furnace without using a hot press. In each of the examples and comparative examples, the final moisture content of the pulp molded article was 5% by weight. Table 1 shows the details of the heating and drying process conditions. The molded body was manufactured to have a substantially cylindrical hollow bottle shape with a weight of 38 g, a height of 240 mm and a body diameter of ø80 mm. Papermaking, dehydration and drying conditions were as follows:

Papermaking conditions Papermaking time 15 seconds

Dehydration conditions Dehydration time 20 seconds, moisture content after dehydration 60% by weight Hot pressing conditions Heating mold temperature 220 ° C, pressing force by core 6 X 10 ⁵

P a

Drying furnace conditions: hot air temperature: 170 ° C, far infrared ray temperature: 450 ° C, hot air volume: 2 m ³ / min. The pulp molded products obtained in Examples 1 and 2 and Comparative Example 1 Then, the deformation of the molded body and the occurrence of bliss were evaluated by the following methods. The results are shown in Table 1.

(Deformation of molded body)

The appearance of the pulp molded product obtained by heating and drying was visually observed, and the presence or absence of deformation was judged by “〇” (no deformation) and “X” (deformed). In addition, the outer diameter of the body of the molded body was measured using a laser measuring machine. The molded body was inverted, and the outer diameter of the torso of the straight part of 45 to 180 mm from the bottom was measured at 2 mm intervals, and the average value and variation (standard deviation, 3) were obtained.

[Generation of prestar in molded product]

The state of the inner surface of the pulp molded article obtained by heating and drying was visually observed, and the presence or absence of blisters was judged by “〇” (no occurrence of blisters) and “X” (presence of blisters). In addition to the evaluation of the deformation of the compact and the occurrence of blisters, the peel strength of the surface of the compact was measured. For the measurement, a disc-shaped plate with a diameter of 1 cm was prepared in the same manner as in the examples and comparative examples. Performed in accordance with P8129. As a result, the measurement result of the peel strength changed from 7 to 11 depending on the pressing condition of the core in the first heating and drying step, but when removing the pulp molded product from the first heating and drying step It was found that the measurement results did not change depending on the water content of the sample.

(Examples 3 and 4 and Comparative Example 2)

Examples 3 and 4 are the same as Example 1 except that the shape of the molded body was changed to the hollow bottle shape and the box shape shown in FIG. 3 was used. Comparative Example 2 was the same as Comparative Example 1 except that the shape of the molded body was the box shape shown in FIG. Table 2 shows the details of the conditions of the heating and drying process. The molded body was made to have a weight of 30 g, a length of 80 mm, a width of 150 mm, and a height of 150 mm. Papermaking, dewatering and drying conditions were as follows.

Papermaking conditions Papermaking time 12 seconds

Dehydration conditions Dehydration time 20 seconds, moisture content after dehydration 60% by weight Hot pressing conditions Heating temperature 200 ° C, pressing by core 4.4 X 1

0 ⁵ P a

Drying furnace conditions: hot air temperature 170 ° C, far infrared ray 450 ° C, Hot air flow 2 m ³ / min The deformation of the molded pulp and the generation of blisters were evaluated for the molded pulp molded products obtained in Examples 3 and 4 and Comparative Example 2 in the same manner as described above. Deformation was performed only by visual observation. Table 2 shows the results. Table 2

As is clear from the results shown in Tables 1 and 2, when heating and drying the pulp mold intermediate only in the drying oven, the drying time in the drying oven becomes longer, and a large drying oven is required. I understand. Further, it can be seen that deformation of the molded body occurs. As is clear from the results shown in Table 1, the pulp molded article of the example had an average outer diameter of the body substantially close to the mold dimension of 8 O mm, and the pulp molded article of the comparative example It can be seen that shrinkage by heating and drying is smaller than that of the body. In particular, in Example 1 and Example 2, the average body diameter of the pulp mold intermediate obtained from the first heating and drying step was smaller than that of Example 2 in which the water content was small. The value is closer to mm, indicating that shrinkage due to heating and drying is even smaller. From the above, the first drying step by hot press and drying oven The second drying step is performed, and the change from the first step to the second step is performed at the time when the moisture content of the pulp mold intermediate falls within a predetermined range. Without drying, the entire drying process is completed in a short time, and the drying equipment is also reduced. Although not shown in the table, the pulp molded product obtained in the example had high surface smoothness and was flexible. Industrial applicability

ADVANTAGE OF THE INVENTION According to the manufacturing method of the pulp molded article of this invention, a drying time can be shortened, a drying facility can be reduced, and manufacturing cost can be reduced. Further, according to the method for producing a pulp molded article of the present invention, the surface strength of the molded article is improved by appropriately adjusting the water content at the time of switching from the first heating and drying step to the second heating and drying step. The density and flexibility are controlled while being kept constant, giving the molded body the required rigidity and flexibility according to its use. Further, according to the method for producing a pulp molded article of the present invention, molded articles of various shapes can be easily produced at low production cost without any restrictions on the design of the molded article. Further, according to the method for producing a pulp molded article of the present invention, a deep-bottom molded article having no seams or thick portions due to bonding can be produced.

Claims

The scope of the claims

1. A method of forming a pulp mold intermediate from a pulp slurry using a papermaking mold and manufacturing a pulp mold molded body by a heating and drying step of the pulp mold intermediate.

In the heating and drying step, a first step of loading the pulp mold intermediate into the recess of a heating mold having a recess having a shape corresponding to the outer shape of the pulp molded article to be molded, and hot pressing the pulp mold intermediate And a second step of removing the hot-pressed pulp mold intermediate from the heating mold and heating and drying in a drying furnace.

2. The method for producing a pulp molded article according to claim 1, wherein the pulp mold intermediate is taken out of the heating mold when the water content reaches 10 to 40% by weight by the hot press.

3. The papermaking molds are composed of a set of split molds in which cavities of a predetermined shape are formed by abutting each other,

Forming a pulp mold intermediate by depositing pulp fibers in the pulp slurry on the inner surface of the cavity;

2. The pulp mold molded article according to claim 1, wherein the pulp mold intermediate is interposed between the heating mold and the expandable and contractible core, and the pulp mold intermediate is hot-pressed by pressing both. Production method.

4. The method for producing a pulp molded article according to claim 1, wherein the heating and drying in the drying furnace is performed by blowing hot air or irradiating infrared rays or far infrared rays.

5. An apparatus for producing a pulp molded article used in the method for producing a pulp molded article according to claim 1, wherein

Transporting the pulp mold intermediate from the first heating and drying unit to the second heating and drying unit based on the moisture content, weight or temperature data of the pulp mold intermediate measured by the measuring device. Apparatus for producing a pulp molded article having means.